Hydrometallurgical processing of ore is often used to recover metal, such as copper, silver, platinum group metals, molybdenum, zinc, nickel, cobalt, uranium, rhenium, rare earth metals, combinations thereof, and the like from ore. In general, hydrometallurgical processes include three steps: leaching (e.g., atmospheric leaching, pressure leaching, agitation leaching, heap leaching, stockpile leaching, thin-layer leaching, vat leaching, or the like) ore to obtain a pregnant leach solution including desired metal ions, purifying and concentrating the pregnant leach solution, using, e.g., a solvent extraction process, and recovering the metal, using, e.g., an electrowinning, sulphidation, precipitation, ion exchange or any other process suitable for recovery of metals.
During a solvent extraction process, the pregnant leach solution is mixed with an organic material that generally includes a diluent, such as oil, and a metal-specific extractant. The leach solution and organic material are mixed to form a dispersion and/or emulsion. The dispersion/emulsion mixture of the pregnant leach solution and the organic material is then allowed to settle to form a depleted aqueous (heavier, bottom) phase and a loaded organic (lighter, top) phase, which includes the desired metal ions. A crud layer, including an emulsion and/or dispersion of organic and aqueous materials as well as fine particles, may also form between the aqueous and organic phases.
The loaded organic phase may be sent to a wash or stripper stage to strip the copper ions into an electrolyte solution for subsequent recovery of the metal. The depleted aqueous phase may be further treated, may be recycled for leaching additional ore, and/or may be forwarded to a secondary metal extraction process for recovery of additional metals.
Unfortunately, separation of the organic and aqueous phases is typically incomplete, with some residual organic material entrained in the aqueous phase and some residual aqueous material entrained in the organic phase. The residual material entrained in the respective phases, especially in the case of organic material entrained in the aqueous phase, increases costs associated with recovering metal from ore, because the organic material is relatively expensive, and any organic material entrained in the aqueous phase may be lost and thus additional organic material is required for the extraction of metal ions. Accordingly, improved articles and methods for improving solvent extraction operation and for reducing an amount of organic material entrained in an aqueous phase associated with the solvent extraction operation are desired.